cpp primer 习题 10.24

这是单词统计的迭代器版本：

/*
** Copyright (C) QPSOFT.COM All rights reserved.
*/
#include<iostream>
#include<map>
#include<utility>
#include<string>
int main()
{
	using namespace std;
	map<string, int> word_count;
	string word;
	//读入单词并统计其出现次数
	cout << "Enter some words:" << endl;
	while(cin >> word)
	{
		//插入元素<word,1>
		pair<map<string, int>::iterator, bool> ret = word_count.insert(make_pair(word, 1));
		if(!ret.second)
			++ret.first->second;//单词出现次数加1
	
	}
	//输出结果
	cout << "word/t/t" << "times" << endl;
	for(map<string, int>::iterator iter = word_count.begin(); iter != word_count.end(); ++iter)
	{
		cout << (*iter).first << "/t/t"
			<< (*iter).second << endl;
	}
	return 0;
}